Aviation in a zero carbon future: what are the options?

Aviation is almost completely dependent on fossil fuels, and together with agriculture and shipping is widely considered a ‘hard to decarbonise’ sector. Partly because of this, aviation has so far been given extra leeway in the setting of climate targets and ambition. The UK’s carbon budgets are, for example, set so as to allow aviation to keep its CO2 output roughly the same as it is today, even as the economy as a whole is required to cut emissions by 80% against a 1990 baseline.

The Paris Agreement and increasing climate ambition

But the Paris Agreement of 2015 has ratcheted up the global ambition on climate change. And as more and more countries now focus on delivering their own emissions reduction plans, there’s increasing evidence that airlines shouldn’t assume they will always be able to buy cheap offsets from developing countries to account for their growing emissions.

The UK climate legislation, which came into force in 2008, was designed to reflect a widely shared ambition to limit the risk of exceeding 2 degrees of global warming. But there’s growing pressure to bring the UK Act into line with the key commitments of the Paris Agreement – to aim to limit warming to no more than 1.5 degrees, and to bring emissions to net carbon zero in the coming decades. This will require a combination of rapid shifts to renewable energy, lifestyle changes, and the use of negative emissions technologies to capture or remove carbon from the atmosphere.

How will aviation fit in?

What will this mean for aviation, in the UK and elsewhere? Will the world have enough sustainable biofuel to power a growing global aircraft fleet, while also meeting demand from other sectors and feeding a growing global population? Will electric aircraft ever be commercially viable, at least for short haul routes as Norway’s airport operator recently believes? And what chance is there for a much wider, more serious conversation about how to limit demand for this inherently energy-intensive sector?

In January this year, AEF took part in a workshop organised by the European NGO T&E on options for in-sector decarbonisation, which brought together academics and policy experts to consider options including electrification, power-to-liquid, and other alternative fuel sources. A summary of the day, and slide presentations are available here.

There are significant barriers to implementing any of these options on the scale and timeframe required, including the need for investment, the limited range likely to be possible from battery powered aircraft, and likely demand from other sectors for sustainable fuel. At AEF we are keen to participate in positive but realistic conversations about the part aviation should play in a ‘net carbon zero’ future including the possibilities for in-sector CO2 cuts from aviation as well as the need for limits on both demand and capacity, over the coming months and years.